NetBeans Servlet MySQL(NetBeans Servlet MySQL)

 这已经解决了 
 
 问题在于参数名称。 
 
 我正在尝试创建一个基本的登录servlet，它将检查员工的登录详细信息。 
 
 但是我的servlet似乎没有与数据库交互，总是将我返回到“tryagain.jsp”。 我究竟做错了什么？ 我正在使用glassfish和netbeans。 我也在库文件中有j / connector驱动程序。 
 
 这已经解决了 
 
 问题在于参数名称。 
 
 这是代码。 
 
package loginServlet;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.sql.*;

/**
 *
 * @author asus
 */
public class Login1 extends HttpServlet {


    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/html");
        PrintWriter out = response.getWriter();

        Connection conn;
        PreparedStatement ps;
        ResultSet rs;
        String DRIVER = "com.mysql.jdbc.Driver";
        String DATABASE_URL = "jdbc:mysql://localhost:3306/northwind";
       String uname=request.getParameter("username");
String passwd=request.getParameter("userPass");
        try {
            // load the driver class
            Class.forName(DRIVER);

            // establish connection to database                              
            conn =
                    DriverManager.getConnection(DATABASE_URL, "jonh86", "ADMIN");
            System.out.println("Connected....");
            ps = conn.prepareStatement("select * from userdata where user_name = ? and password = ?");
            ps.setString(1, uname);
            ps.setString(2, passwd);
            rs = ps.executeQuery();
            if (rs.next()) {

            RequestDispatcher rd = request.getRequestDispatcher("WelcomeServlet");
            rd.forward(request, response);

//out.println(rs.getString(2));
            } else {
                RequestDispatcher rd = request.getRequestDispatcher("tryagain.jsp");
            rd.include(request, response);
            }
        } 


        catch (Exception e) {
            System.out.println(e);
        }

    }

}

THIS HAS BEEN SOLVED
 
The problem lay with the parameter names.
 
I am trying to create a basic login servlet that will check the login details of employees.
 
However my servlet doesn't seem to be interacting with the data base and always returns me to the "tryagain.jsp". What am I doing wrong? I am using glassfish and netbeans. I have j/connector driver in the library files as well.
 
THIS HAS BEEN SOLVED
 
The problem lay with the parameter names.
 
Here is the code.
 
package loginServlet;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.sql.*;

/**
 *
 * @author asus
 */
public class Login1 extends HttpServlet {


    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/html");
        PrintWriter out = response.getWriter();

        Connection conn;
        PreparedStatement ps;
        ResultSet rs;
        String DRIVER = "com.mysql.jdbc.Driver";
        String DATABASE_URL = "jdbc:mysql://localhost:3306/northwind";
       String uname=request.getParameter("username");
String passwd=request.getParameter("userPass");
        try {
            // load the driver class
            Class.forName(DRIVER);

            // establish connection to database                              
            conn =
                    DriverManager.getConnection(DATABASE_URL, "jonh86", "ADMIN");
            System.out.println("Connected....");
            ps = conn.prepareStatement("select * from userdata where user_name = ? and password = ?");
            ps.setString(1, uname);
            ps.setString(2, passwd);
            rs = ps.executeQuery();
            if (rs.next()) {

            RequestDispatcher rd = request.getRequestDispatcher("WelcomeServlet");
            rd.forward(request, response);

//out.println(rs.getString(2));
            } else {
                RequestDispatcher rd = request.getRequestDispatcher("tryagain.jsp");
            rd.include(request, response);
            }
        } 


        catch (Exception e) {
            System.out.println(e);
        }

    }

}

原文：https://stackoverflow.com/questions/19172606